Contradiction (Logical)

Logical contradiction (as opposed to DIALECTICAL CONTRADICTION) is a matter of simultaneously saying, putting forward, or defending both some specific and definite statement and the denial of that self-same statement. Or, in other words, it the conjunction of a statement with its own negation, p & not-p.

Thus the statement that "Socrates was a man." and "Socrates was not a man." are logically contradictory if both refer to the same male human being, Socrates of Athens, who lived from approximately 469 to 399 B.C.E. and if both mean by "was a man" exactly the same thing. If one of the statements refers to a race horse by the name of Socrates, while the other refers to the famous philosopher, then the two statements are not logically contradictory. If both statements refer to the same man, but one of them means by "was not a man" that Socrates was cowardly (whether or not he actually was cowardly in any respect), then also the two statements do not contradict each other. Similarly, "The sky is blue." and "The sky is not blue." do not contradict each other if one refers to the color of the sky on Monday, while the other to the color of the sky on Tuesday (when it might be gray).

But because all these qualifying quibbles are not always clear and obvious, there have been those who have refused to condemn logical contradiction. (Or, perhaps they were even smarter than that, and were actually defending dialectical contradiction!) How, for example, do you interpret the following couple of lines?

When we risk no contradiction,
It prompts the tongue to deal in fiction.
—John Gay, "Fables", I, "The Elephant and the Bookseller"